STAT1-deficient mice display delayed blood rebounds following 5′-FU–induced myeloablation. (A) Representative flow cytometry plots showing cell cycle analysis using intracellular staining of Ki-67/DAPI. G₀ phase is defined as Ki-67⁻ and 2n DNA, G₁ as Ki-67⁺ and 2n DNA, and S-G₂-M as Ki-67⁺ and DNA > 2n. (B) Bar graphs showing comparable cycling status in ESLAM HSCs from STAT1KO and WT control mice. (C) STAT1-deficient mice showed delayed rebounds of platelets and white blood cells (WBC) following a single dose of 5-FU injection (150 mg/kg). (D-E) Bar graphs showing reduced spleen size in STAT1-deficient mice at days 12 and 15, respectively. Data are shown as mean ± standard error; asterisks indicate significant differences by Student t test (∗∗∗∗P < .0001; ∗∗∗P < .001; ∗∗P < .01; ∗P < .05).